Ammunition used in firearms consists of four components: an initiator or primer, a casing, propellant or gunpowder, and a bullet or projectile (also called tip). The casing is a cylinder that acts as a support for the primer, the projectile and the propellant contained within the casing.
Ammunition has typically been formed from metal. The vast majority of current casings are made of “military brass”, called brass 70/30. The most widely used metal is brass, plated steel, steel and, in some cases, aluminum.
Attempts have been made to produce useful ammunition form materials other than metal. For example, U.S. Pat. Nos. 2,654,319; 2,862,446; 6,845,716 and 7,213,519 all disclose ammunition having at least one component formed from a polymeric material. However, all of the disclosed non-metal ammunitions have one or more shortcomings that have prevented wide use, if any, in weapons such as rifles and pistols. For example, prior non-metal ammunitions tend to split (i.e., individual components separate from one another) during firing. In other words, prior non-metal ammunitions do not possess an ammunition structure that regularly withstands the forces within the ammunition during firing.
Efforts continue in the development of ammunition casings that (1) provide one or more unique features, (2) are relatively easy to manufacture and use, (3) provide an aesthetically pleasing look for the user and other viewers, (4) are economical to make and use, and (5) provide an ammunition structure that withstands forces within the ammunition during firing.